APELAFICO - pair design study

1 Data set overview

  year    dataSet       station                freq   date_start    date_end   pairing      type
------ ---------- ------------- ------------------- ------------ ----------- --------- ---------
  2021    2021-BE       grafton   70kHz and 200 kHz    7/12/2021   8/30/2021         2   control
  2021    2021-BE    birkenfels   70kHz and 200 kHz    7/12/2021   8/30/2021         1   control
  2021    2021-BE        cpower                Lost    7/12/2021   8/30/2021         2       OWF
  2021    2021-BE       belwind   70kHz and 200 kHz    7/12/2021   8/30/2021         1       OWF
  2023    2023-BE       belwind   70kHz and 200 kHz     7/5/2023    9/3/2023         1       OWF
  2023    2023-BE        cpower              70 kHz     7/5/2023    9/3/2023         2       OWF
  2023    2023-BE    gardencity   70kHz and 200 kHz     7/5/2023    9/3/2023         1   control
  2023    2023-BE       grafton   70kHz and 200 kHz     7/5/2023    9/3/2023         2   control
  2023   2023-BSW   267814 BSW3               70kHz     5/7/2023   6/16/2023         2       OWF
  2023   2023-BSW   267838 BSW4   70kHz and 200 kHz     5/7/2023   6/16/2023         1       OWF
  2023   2023-BSW   274174 BSW1   70kHz and 200 kHz     5/7/2023   6/16/2023         1   control
  2023   2023-BSW   278093 BSW2   70kHz and 200 kHz     5/7/2023   6/16/2023         2   control
  2024    2024-BE        cpower   70kHz and 200 kHz    10/4/2023   12/4/2023         1       OWF
  2024    2024-BE       grafton   70kHz and 200 kHz    10/4/2023   12/4/2023         1   control

• Most WBAT data were recorded in 5 minute intervals, sequentially at 70 kHz and 200 kHz
• Some WBAT data sets had longer span (10-15 minutes)
• All data sets were standardized to intervals between 3.5 and 5 minutes by randomly sampling the full sampling interval
• SA are compiled as mean SA for each interval in a given hour
• CPOD data are sorted per hour, also with absence/presence

The time series are shown below for the CPOD data (1.1) and WBAT data at 70 kHz (1.2) and 200 kHz (1.3).

Figure 1.1: Time series of CPOD recordings per pair and data sets.

Figure 1.2: Time series of WBAT recordings @70khz per pair and data sets.

Figure 1.3: Time series of WBAT recordings @200khz per pair and data sets.

2 Comparison of fish biomass - OWF vs control

From Figures 2.1 and 2.2:

• More biomass at the “control sites”
• Clear diurnal patterns with higher biomass at night
• Results are consistent at both 70 kHz and 200 kHz though the contrast between OWF and control is more pronounced at 70 kHz
• There is clear variations between sites (1.2 and 1.3)

Figure 2.1: Boxplot of acoustic density (SA) @70kHz at OWF and control sites for day and night periods.

Figure 2.2: Boxplot of acoustic density (SA) @70kHz at OWF and control sites for day and night periods.

3 HP presence and activity

From Figures 3.1, HP presence is higher at the control sites. When standardized as hour positive minutes, one can observed comparable results 3.2.

Figure 3.1: Boxplot of Harbor porpoise daily presence at control and OWF sites.

Figure 3.2: Boxplot of Harbor porpoise hour positive minutes at control and OWF sites.

4 Fish biomass vs HP presence

HP presence seems to be associated with higher biomass, i.e. Figures 4.1 and 4.2. Though there is variations in day/night periods and between sites (Figure 4.3 and 4.4).

Figure 4.1: Boxplot of acoustic density (SA) @70kHz with presence and absence of Harbor porpoise at OWF and control sites.

Figure 4.2: Boxplot of acoustic density (SA) @200kHz with presence and absence of Harbor porpoise at OWF and control sites.

Figure 4.3: Boxplot of acoustic density (SA) @70kHz with presence and absence of Harbor porpoise. Results are shown per data sets over day and night periods.

Figure 4.4: Boxplot of acoustic density (SA) @200kHz with presence and absence of Harbor porpoise. Results are shown per data sets over day and night periods.

5 Fish biomass vs HP PPM

There is a possible increase of PPM biomass, i.e. Figures 5.1 and 5.2. The increase is more pronouced at 200 kHz. The results are further broken down in to day/night periods in Figures 5.3 and 5.4

Figure 5.1: Boxplot of acoustic density (SA) @70kHz in different porpoise positive minute bins. Results combine data at the control and OWF sites.

Figure 5.2: Boxplot of acoustic density (SA) @200kHz in different porpoise positive minute bins. Results combine data at the control and OWF sites.

Figure 5.3: Boxplot of acoustic density (SA) @70kHz in different porpoise positive minute bins. Results combine data at the control and OWF sites for day/night period.

Figure 5.4: Boxplot of acoustic density (SA) @200kHz in different porpoise positive minute bins. Results combine data at the control and OWF sites for day/night period.